Confused..

I have a few questions about my current situation.

First of all I was 3 days late on my period, so I took a pregnancy test and tested positive. The next morning I started bleeding and started having pains. We went to the Emergency Room to see what was going on. They did a urine and a blood test to see if I was pregnant and they said the test came back negative. I read online that blood tests can be wrong depending on medications (I took 2 otc ibuprofen for the pain before we went to the hospital) and if you drink a lot before the test is taken or if its too early to tell. They told me i had a uti. I have been taking antibiotics for it. I have been feeling very sick the past couple of days. We are to set up an appointment with a gynocologist sometime this week about the situation and to see why it mightve have happened but i wanted to know if i could still be pregnant. We have been trying to conceive for almost 3 years. I have been trying to chat with a doctor without having to pay. Can i please get some advice could i still be pregnant?